Helical brush means and method for making the same



L. E. JONES July 13, 1965 HELICAL BRUSH MEANS AND METHOD FOR MAKING THE SAME Filed June 27. 1961 3 Sheets-Sheet 1 Ila/v55 flrraezveys.

HELICAL BRUSH MEANS AND METHOD FOR MAKING THE SAME Filed June 27, 1961 L. E. JONES July 13, 1965 3 Sheets-Sheet 2 INVENTOR. LLOYD E, IIc JA/Es flrroeusy s.

L. E. JONES July 13, 1965 HELICAL BRUSH MEANS AND METHOD FOR MAKING THE SAME 3 Sheets-Sheet 3 Filed June 27, 1961 INVENTOR. E, (IO/V55 fir roe/vs YZ Pdtentedduly 1a, 1965 P ice 3,193,865 HELICAL BRUSH MEANS AND METHGD FGR MAKING THE SAME Lloyd E. Jones, Arcadia, Califi, assignor to Industrial Brush Company, Arcadia, Calii'., a corporation of California Filed June 27, 1961, Ser. No. 119,869 11 Claims. (Cl. 15-182) This invention relates to a means and method for making a brush means having radially extending layers of bristles disposed in a helical arrangement, such brush means having utility in street and industrial sweeping applications. The invention more particularly relates to an apparatus and method adapted to use a pre-assembled brush strip means of known construction and heretofore utilized in only straight line brush strip installations.

Various brush constructions have been proposed wherein the bristles are arranged in helical fashion about a brush core member. Initially such prior proposed brush means included a core member provided with an external threadlike groove therein in which bristles were laid and then retained by a continuous Wire or cable element placed across said bristles and in said groove and then tightened to retain the bristles. Later brush constructions of helical type included a similar core member having external grooves in which a brush strip was wound, the brush strip including a channel form member holding a layer of folded bristles retained in the channel form member by a wire element. This brush strip construction was very suitable when used in straight line installations but when such a strip was curved to provide a helical or radial type brush means various problems arose. These problems were met by prior proposed brush constructions as shown in Patents 1,963,044, 1,963,045, 2,303,385 and 2,755,400. In each instance the problem was attempted to be met by modifying the brush strip construction as the brush strip was formed as by providing inwardly directed teeth or protuberances to overlie and to contact the retaining element so that the retaining element would be held in fixed relation to the channel form brush strip member. After this was accomplished the specially constructed brush strip was then formed into a circle, a helix, or a spiral.

Some of the problems encountered in the making and forming of a brush strip means of helical form where the layers of bristles extend radially from a brush core member and from a brush strip member wound into a helix include the loosening of the bristles in relation to the retaining element and the brush strip base member. When a pre-assembled known brush strip is wound into a circle or into helical form the side walls of the channel form base member are stretched, the outer longitudinal edges of said side walls being stretched the maximum and as a result the crimping pressure previously imparted to the side walls during forming of the brush strip was reduced and substantially relaxed. Thus the bristles after winding into a circle were not as tightly held in the channel form brush strip base member and during sweeping were relatively rapidly loosened. In use the loosening of the bristles with respect to the retaining element and the base strip member is caused by constant working of each bristle as it engages a surface being swept and flexes in a direction generally longitudinally with respect to the elongated brush strip base member. Such constant flexing in such direction produces wear of the bristle filament at its contact with the retaining element and since such cylindrical brush means are usually rotated at a relatively rapid rate the bristles are subjected to a combination of flexing and centrifugal forces that may soon cause sufficient Wear so that bristle filaments are thrown out of the brush means.

The material of the brush bristle or filament also affects this problem. With natural brush filaments the surface and texture of the natural filament which were relatively non-slippery tended to reduce the effect of such action. However natural filaments are becoming more diilicult to obtain and synthetic bristle filaments which have characteristics of greater life and other desirable features are being used in such sweeping applications. Synthetic brush bristles or filaments are quite smooth and slippery and as a result are more difiicult to hold and retain in a brush strip base member.

The present invention therefore contemplates a means and a method for making a helical brush means which includes advantages not found in the prior proposed brush constructions and methods of making such prior constructions While at the same time providing a helical brush means in which the brush filaments are securely retained and held.

The method of the present invention contemplates using a preformed pre-assembled brush strip means including a brush strip base member in which bristles are held by a wire retainer element and in which side Walls of the base member have been subjected to usual continuous crimping in order to retain the bristles, base member and retainer element in assembly. Such a strip is of a construction which may normally be used in straight line brush strip installations. The method of the present invention contemplates continuously feeding such a brush strip means in' a straight linear path and then directing the brush strip means into a selected helical path having a predetermined radius of curvature. After the brush strip means has moved alon said helical path for a selected distance during which the side walls of the base strip member have been stretched the side walls are inwardly indented at spaced intervals to delineate groups of bristles. After the indenting has been performed the brush strip means is further directed along the selected curved path to form a helical brush means. Thus the method of the present invention forms indentations in side Walls of the base member and imparts restraining forces longitudinally directed with respect to the base member to the groups of bristles so that each bristle or filament in the group is held against radial outward movement by the retainer element and is held and restrained against longitudinal displacement by the indentations.

An object of the present invention is therefore to provide a new and novel method of making a helical brush construction.

Another object of the invention is to disclose and provide a method for making a helical brush construction wherein indenting of a brush strip base member is performed while the brush strip means is continuously moved in a curved path.

Still another object of this invention is to disclose and provide a method for making a helical brush means wherein jaw elements are actuated in timed relation to the rate of movement of the brush strip means for indenting the brush strip base member at selected spaced intervals.

A further object of the invention is to provide a method for making a helical brush means wherein a crimping jaw assembly is pivotally mounted and resiliently limitedly restrained for limited movement in the direction of travel of a brush strip means.

An important object of the invention is to provide a method wherein walls of a brush strip member are first stretched to a desired configuration and wherein after stretching said walls are indented at spaced intervals to positively retain brush filaments in the brush strip member and to hold defined groups of filaments between said'indentations against movement longitudinally of the brush strip member.

Another important object of this invention is to disclose a helical brush means wherein the core member thereof is provided with means adjacent each end of the core member cooperative with the spaced indentations and V bristles to lock and hold the core member again-st displace-v ment relative to the base member of the brush strip from the following description of 'the drawings which show an embodiment of the invention. =7

In the drawings: 7 FIG. 1 is a top plan view of an apparatus vention.

FIG. 2 is a fragmentary sectional view taken from the plane indicated by line IIII of FIG. 1.

FIG. 3 is a fragmentary sectional view taken in the plane indicated by line III-,-HI of FIG. 2.

FIG. 4 is a fragmentary sectional view taken in the plane indicated by line IVIV of FIG. 2.

FIG. 5 is a fragmentary view taken in the same plane as FIG. 4 showing the jaw members in crimping relation.

FIG. 6 is an enlarged fragmentary view of the jaw ends of the crimping means shownin FIG. 5;

FIG. 7 is a sectional view taken in the plane indicated by line VIIVII of FIG. 6. v I

FIG. 8 is .a sectional view taken in the plane indicated by line VI=II--VIII of FIG. 7.

FIG. 9 is a fragmentary end sectional view of a helical brush means made'according to this invention. Generally speaking an apparatus used in the present inused in the in- 'vention is indicated at and may generally comprise a frame means 16, a mandrel carriage 17, a rotatable mandrel18 on said carriage 17, drive means 19 for the carriage,

and a crimping or staking means 20 at one side of frame means 16 and opposite to the feed. path of a preformed, pro-assembled brush strip means 45. The staking means 20 generally includes a jaw assembly 21 extending towards mandrel 18, actuating means 22 for said jaw assembly, and stationary support means 23 for said crimping means.

The frame means 16 may include structural frame members suitably arranged to form an open framework and to provide spaced parallel longitudinally extending rail mem- V 4 at a selected .rate of rotation while the carriage is moved in one direction by the pinion gear 54 and rack teeth 55 at a predetermined relatively slow linear rate of speed.

The crimping or staking means 20 may comprise a support frame means, 60 which may be fixedly secured to frame means 16 or which may be a stationary separate stand or support located adjacent the frame means 16 at intermediate ends thereof. In this example'the support Tmeans 66 may be. connected to the frame means 16. Provision may be made for location of the support means 60 adjacent one or the other end of the frame means 16 depending upon the length" of the helical brush means to be made. In this example, the central location of the support means 60' permits movement of mandrel18 on the carriage '17 in either longitudinal direction while a brush strip is being wound therearound.

' The jaw assembly 21 may be pivotally supported from the support means 60 by a pivot shaft 61 carried in bearing means 62 secured to the top horizontal surface of the support means 60. The jaw assembly 21 includes vertically spaced rigidly interconnected horizontally extending jaw support members 64 and 65, the outer edge portions of each jaw support member 64 having connection with the pivot shaft 61. A compression spring 66 supported bysupport means 60 intermediate ends 'of the jaw members 64 normally holds the jaw assembly 21 in selected position with the jaw members 64 and 65 disposed below and above a horizontal plane passing through the 'axis of the mandrel 18. Adjacent their inner free ends, sets of members 64 and 65 are provided interconnecting vertical plates 63 and parallel vertically disposed pivot pins 69 are provided adjacent said plates. An elongated jaw member 70 is pivotally mounted on each pin 6? and extends between jaw support elements 64 and 65 and in l cylindrical surface of mandrel :18. As best seen in FIG.

bers 30 provided with inverted V-type tracks31. Tracks 31 may extend for the length of frame means 16 and sufiicient to permit movement of carriage 17 in either direction with'respect to the staking means 20 for making helical brush means having turns in either right or left direction.

The mandrel carriage 17 may include a. rectangular frame 33 including longitudinally extending side members 5 each jaw element 71 may include a crimping face 72 disposed at a selected angle with respect to the axis of the jaw member 70 and adapted to pressure engage the 34 interconnected by transverse end members 35 and inter- J mediate transverse members 36. Side members 34 may be of channel section and adjacent. each end may be provided with an outwardly extending horizontal bracket 37 having a depending leg 38 in which is rotatably mounted a wheel 39 for rolling engagement with track 31. Centrally and extending longitudinally between intermediate transverse members 36 may be rotatably supported by bearing means 40 the mandrel 18 of selected outer diameter. The mandrel 18 may comprise a smooth surfaced upper longitudinal marginof a brush s-trip metal base member 73 to impress or indent oppositely disposed protuberances 'or indentations 74, FIG. 6. Each jaw element 71 and crimping face 72 may be made of suitable hardened material and may have any selected shape or configuration. In this example the jaw or crimping face 72 may be generally rectangular with its length extending laterally of the base member 73 so as. to provide radially or laterally directed indentations in the side walls 96 of the brush strip member 73.

The opposite end of each jaw member 70 may extend into proximity with pivot shaft 61 and may carry cam cylindrical Wall provided with a'spider member 41 at 1 each end, for carrying a mandrel shaft 42. At each end, .the mandrel may be provided with a clamp 43 for connectionwith one endof a brush strip means 45 which is to be formed into a helical brush means, only one clamp 43 being used during the forming of the brush means.

Means for driving .the carriage 17 and for rotating the mandrel 18 in selected timed relation may comprise an extension 46 of mandrel shaft 42 for connection with a sprocket 47 driven by chain 48 through a pinion sprocket 49 connected through a gear box'50 to a suitable. motor 51. The shaft extension 46 may extend beyond-the end frame member 35 for connection through a suitable ear system schematically indicated at 53 to a pinion drive gear 54 which engages rack teeth 55 carried by and beneath the side frame members 34 of thecarriage 17; Gear ratios are so selected that mandrel 18 will be driven follower means, in this example, a freely rotatable roller or wheel 75. Beneath wheels'75 and on the bottom jaw support members 64 may be provided a transverse-cross slide 76 having a top face 77 upon which the bottom surfaces'ofthe outer ends of jaw members 70'may be slidably supported. ;A spring 78 adjacent cross slide 76 biases the jaw members toward open position.

, Means for alternately opening and closing jaw members 79 by pivotal movement about-their axes 69 may include an elongated cam member 80 disposed between cam rollers 75. Cam member 80 has a selectively configured cam edge face 81 for actuation of the jaw members 70. Cam edge face '81 includes a cam face portion 81a for closing jaw elements 71 for applying crimping pressure in a relatively steady manner. Maximum crimping pressure occursat points P spaced apart a maximum distance on the elongated cam member. Immediately after point P, cam face portion 81b rapidly positively opens the jaw elements 71 and permits release and withdrawal of ele ments 71 from the indentations. Thus the cam member quickly disengages the jaw members Whom the brush strip base member 73. The cam member 80 may be mounted on a vertical shaft 82 depending from a gear reduction means generally indicated at 83 which is connected by a suitable drive means 84 to a motor 85. The gear reduction means 83 is selected so that the cam member 80 will rotate at selected revolutions per minute correlated with the linear rate of advancement of the brush strip means 45 on the mandrel so as to provide indentations at selected spaced intervals along the brush strip member 73.

The crimping means 20, as noted above, is supported on pivot shaft 61 and compression spring 66. Downward movement of jaw elements 71 when in crimping contact with a brush strip member may thus be provided during a crimping operation. To facilitate return of the means 20 to normal position, an upstanding post 87 may be provided on support means 23, said post being connected to one end of a tension return spring 88 which is connected at its other end at 39 to crimping means 20 adjacent motor 85.

It will thus be noted that the tension spring 88 and the compression spring 66 resiliently and yieldably hold the jaw assembly 21 in a selected generally horizontal position on the pivot shaft 61. The assembly is normally biased upwardly by springs 66 and 88 and is limited in upward movement by contact of the top face of member 65 by a stop element 92 carried at the upper end of a bar 93 which is secured in any suitable manner to the support frame means 23.

The brush strip means 4-5 which is to be formed into a helical brush means may comprise brush strip base member 73 of U-section or channel section having side walls 96 between which may be held bristles or brush filaments 97 of selected length by a wire retainer element $8. The brush strip member 73 is made of a metal materialwhich is relatively malleable and soft. The manufacture of such a brush strip means is well known and normally comprises laying a strip of flat metal stock on a conveying means and while the strip is advanced bristles or brush filaments 97 are laid thereacross and the wire element 98 is then laid on top of the center portion of the bristles. As this assembly is advanced the side walls 96 are bent and curved upwardly to form the U-section with slightly inwardly inclined side walls and are then subjected to a continuous crimping or clamping action along longitudinal margins or edge portions to provide a stressed zone which causes the side walls to firmly grasp and frictionally hold bristles 97 in the brush strip member 73. Just after such a brush strip is so formed it may be fed in a linear straight line of travel to the mandrel as indicated in FIG. 2 and the lead end may be secured against movement relative to the mandrel by the clamp 43.

In practicing the method of this invention the machine which forms the brush strip may be operated so as to advance such a pre-assembled, preformed brush strip means to mandrel 18. As the brush strip means 45 advances at a selected rate of travel the mandrel 18 is rotated so that the peripheral speed of the mandrel cylindrical surface is at least equal to or slightly greater than the speed of advancement of the brush strip means 45. As mandrel 18 is rotated the brush strip means 45 is caused to bend around the surface of the mandrel and after it has been turned approximately 90 it will be apparent that the side walls 96 of the strip base member 73 will have been longitudinally or peripherally stretched with the greatest stretching occurring at the longitudinal free edges of the side walls. It will be apparent that such stretching of side walls 96 has a tendency to loosen the crimping pressure engagement of the side walls with the brush bristles 97. Such stretching will be completed during 90 turning of the mandrel and at approximately this point the jaw members 70 receive therebetween the layer of bristles 97 and are actuated in timed relation with the turning of the mandrel so that the jaw elements '71 will indent or crimp the side walls 96 at preselected spaced intervals along their length at said stressed zone. Thus such crimping or indenting of the side walls 96 after maximum stretching has occurred will tend to provide longitudinally arranged groups of bristles which are restrained within the base member 73 not only by some of the initial crimping pressure imparted to the side walls, but also primarily by the indentations formed therein by jaw elements 71 after turning on the mandrel. When such indentations are formed at spaced intervals of approximately one-half to one inch it will be apparent that flexing of bristles 97 during operation will not produce loosening of the bristles and they will be held firmly therein.

As the brush strip 45 continues its path around the mandrel 18 and reaches a point approximately diametrically opposite to the jaw elements 71 a pressure roller 100 urges the brush strip 45 in an axial direction so as to displace it somewhat from the plane in which the advancing straight brush strip contacts the mandrel at the top thereof. Part of this axial displacement is also effected by the advancement of the carriage 17 by the rack and pinion drive means. The pressure roller 103 may be carried by an upstanding member 101 secured in suitable manner to the frame means 16. The member 101 may be extended upwardly beyond the level of the incoming brush strip 45 and provides a connection for a transversely extending suitably configured or bent bristle deflector member 102 which extends across the top of the mandrel and which may be releasably connected at 103 to member 101. At its opposite end the deflector member 102 may be pivotally connected at 164 to an upstanding support member 105 carried by a frame member of the frame means 16. Thus as the brush strip means 45 completes one turn about the mandrel and successive turns, the bristles 97 thereof are deflected away from the incoming brush strip means 45 so as to not interfere with the bristles thereof. As the mandrel continues to rotate to provide additional turns of the brush strip means 45 on the mandrel the carriage is progressively advanced by the carriage drive means including the rack and pinion means 54 and 55 so that the formed turns are continually moved away from zone of operation of the jaw elements 71.

After a selected number of turns have been made on the mandrel the brush strip means 45 may be cut adjacent the top of the mandrel or adjacent the point of tangency of the fed brush strip means with the mandrel and the helical brush means removed from the mandrel by sliding the same off one end of the mandrel 18. To facilitate such removal frame member 36 which supports one of the mandrel shaft bearing means 40 may be pivotally connected at to one side frame 34 and be releasably connected at 111 by a stud and slot connection to the opposite side frame 34. The mandrel shaft may include a coupling 112 of well known form which upon disassembly will permit the frame member 36 to be moved to one side to allow unobstructed removal of the helical brush means. The mandrel 18 may be supported by other means, such as a sling, during this removal operation.

The helical brush means thus formed may be then associated with a brush core member provided with an external threaded or spiral groove by simply feeding the helical brush means on to the threaded core member while the core is rotated. After the helical brush means has been completely threaded on the core member one end of the brush strip means may be secured thereto. The other end of the brush strip means may be secured to the core member in suitable manner after the core member has been slightly further rotated in order to tighten the helical brush strip in the threadlike grooves by reducing the internal diameter of the helical brush means.

It should be noted that the arrangement of the bristles 97 in the brush strip base member 73 is such that the indentations not only provide opposed inwardly extend- 7 7 ing indentations or protuberances in side walls 96 of the base member 95 but that they also press against those portions of the bristles which lie within the base mem ber '73. The protuberances are preferably provided adjacent the longitudinal edges ofthe side walls 96and' terminate at inner ends thereof spaced above the retainer element 93. Tightly compressed between the protuberances and retainer element 98 may be one or more bristle portions which firmly lock and fix the bristles in thebase strip member 73. Such longitudinally spaced firmly locked bristle portions provide fixed retainer means which hold each group of bristles from longitudinal dis placement relative to the base strip member.

It will be understood that when natural brush fila- V ments are used the resiliency of the natural filament will dented by the staking means of this invention so that the filaments are more or less formed into groups and'tight-v ened in thebase member '73. It will be understood that the manner and time of placing the indentations in the strip base member '73 in accordance with the present invention prevents any further loosening of the bristle filaments and that such indentations by'preventing any relative movement between the filaments and the base member during sweeping thereby virtually eliminates weartof the filament in the base member.

It will also be understood that when the formation of the indentations have been eXemplarily accomplished by the crimping jaws described above, other means may be used to indent the base member 73. For example, such indentations during coiling of the brush strip. may be formed by a suitable arrangement. of toothed wheels or gears.

It will be noted that as the brush strip means is fed to and turned around the mandrel the wire element 98 may also be somewhat stretched and tends to more firmly grasp the folded portions of the bristles within the base member 95. Since this tends to tension the element 98 it is sometimes desirable to close the ends of the brush strip member after the helical brush means has been formed by overfolding a side wall or bottom wall of the base member. The end of the wire retainerelement may be secured to such closure end as by brazing or welding.

Since in a sweeping operation the brush filaments flex upon contact witha surface and then return to normal position, impact forces intermittently transmitted in one direction by the filaments to the core member 98 may.

tend to produce a ratchet-like effect on the core member which may ultimately produce longitudinal displacement of the core member relative to the strip member'73. Means to prevent such displacement may include an enlarged lock element 120 of relatively soft metal material bonded as by brazing, welding or soldering to the core member in spaced relation to each end thereof before' the core is assembled with the brush filaments and base member. Thus when the brush strip means is formed and then directed over the mandrel and crimped, the

O 0 base member. It will be understood that the core member with locking elements at each end is not required to 'be' precisely positioned relative to the base member in assembly of the brush strip means because of theabove described action of the locking element.

It will be noted that a helical brush means formed as above described and assembled with a core member will afiord a cylindrical brush having groups of brush filaments which provide an arrangement of bristle ends particularly effective for a sweeping operation. The amount of brush filaments per unit length of the strip may be reduced becauseiof the mutual lateral support of the filaments in each group during sweeping; in some instances the amount of filament material may be reduced in half.

Various modifications and changes may be made in the means and method-described above, and all such changesand modifications .coming withinthe scope of the appended claims are embraced thereby.

. I-claim:

1. A method of making a brush means of helical form from a preassembled brush strip, means including a 1011? gitudinally extending layer'of folded bristles, a retaining Y element therefor, and a channel-like base member having sidewalls continuously crimped adjacent their longitudinal edges for retaining said bristles and retainer element; the steps of: advancing the preassembled brush strip means in V a linear path; continuously pulling .said strip means into a curved path of selected radius for uniformly longitudinally stretching the metal in the side walls in the base member along corresponding lines of curvature; inwardly indenting said side walls at spaced intervals at'a point in said curved path after said side walls have been stretched to delineate groups of bristles; and continuously moving said brush strip means along said curved path to form a helical brush means. '1

2. A method as stated in claim 1 including the step of: spacingthe brush strip means as it is further directed along said curved path from said point at which indenting occurs.

3, A method as stated inclaim 1 including the step of:

continuously moving said brush strip means in said curved path and indenting said side walls in timed relation with respect to said movement of the strip means.

4. A method of continuously forming a helical brush means from a preformed preassembled brush strip means including a channel-like base member, a generally uniform layer of bristlesextending from said base member, and a retainer element for said bristles within said base member, comprising the steps of: longitudinally moving said preassembled brush strip means into a curved path at aselected continuous rate of movement; forming a plurality of opposed spaced indentations in said base member while spaced indentations 74,- the enlarged lock element 120,

and the filaments 97 compressed therebetween coact to positively'lock the core member in the, base member. Such locking action will occur whether the lock element is located immediately at the indentations or between the indentation since the length of the lock element is preferably at least one-half the distance between indenta tions. The soft metal of the lock element may partially deform during crimping if it is located at the indentations said brush strip means continues its movement in said curved path; and directing said brush strip means along a continuation of said curved path to form a helical brush means.

i '5. A method as stated in claim 4 including the step of: intermittently moving indentation forming means in the direction of movement of the strip means for forming of the indentations. V

6. A method as stated in claim 4 including the'step of continuing the strip means in its curved path through greater than 360 and spacing the curved strip means from the point at which indentation forming occurs.

7. A method of continuously forming a helical brush means from a preformed, pre-assembled brush strip means including a channel-like base member, a layer of bristles extending from said base member, and a retainer element for said bristles within said base member, comprising the steps of: pulling said pre-assembled brush strip means into coils around a rotating mandrel, forming indentations in side walls of said base member at spaced intervals mandrel axially for axially spacing adjacent turns of said coil.

8. A method for continuously forming a helical brush means from a preformed, pre-crimped, pre-assembled brush strip means including a channel-like base member having side walls with longitudinal edge portions, a generally uniform layer of bristles extending from said base member between said side walls, and a retainer element for said bristles within said base member, comprising the steps of: feeding said pre-assembled brush strip means along a selected path to a rotating mandrel, pulling said brush strip means into a curved path by said mandrel at a selected continuous rate of speed; intermittently forming spaced indentations in longitudinal edge portions of said side walls While said brush strip means passes an indenting station externally of said mandrel; and slowly advancing said mandrel axially with respect to said indenting station while continually pulling said brush strip means on to said mandrel.

9. In a method of continuously forming a helical brush means including a channel-like base member having side walls with edge portions, a layer of filaments folded in said base member and extending therefrom, and a retainer element for the filaments within the base member, including the steps of: longitudinally moving said base member, filaments and retainer element into a curved path at a selected continuous rate of movement, said edge portions being deformed to provide a stressed zone for clamping said filaments; forming a plurality of spaced indentations in each edge portion at said stressed zone while said base member, filaments and retainer element continue their movement in said curved path; and directing said indented twice stressed assembled base member, filament and retainer element along a continuation of said curved path to form a helical brush means.

10. A continuous helical brush strip means comprising: a continuous helical brush strip member having continuous spaced imperforate side walls inclined inwardly, a core member between said side walls, brush filaments extending between said side walls and beneath the core member, said side walls having longitudinally extending edge margins initially pressed toward each other to provide a deformed stressed zone continuous along and at top portions of the side Walls for clamping said filaments in addition to the inward inclination of said side walls, said edge margins at said zone being peripherally stretched, said edge margins at said zone having a plurality of spaced indentations therein to further stress and deform said zone, said edge margins between said spaced indentations converging against said filaments in opposed peripheral curves, said indentations terminating with inner ends thereof spaced above said core member for clamping retention and grouping of said filaments.

11. A continuous helical brush strip means comprising: a generally U-section brush strip member of continuous helical form including a bottom wall and spaced side walls having longitudinally extending top edge margins, a plurality of brush filaments carried between said side walls; and a retainer member holding said filaments within said brush strip member; said side walls and said edge margins being inclined inwardly and converging against said filaments with said edge margins being under initial continuous clamping pressures against said filaments for the length of said edge margins, a plurality of longitudinally spaced transversely extending indentations in only each edge margin and imparting additional closing pressures on said edge margins at spaced intervals, said edge margins being peripherally stretched, said edge margins between said spaced indentations having said closing pressures slightly less than said initial clamping pressures while maintaining convergence of said edge margins of the side walls against said filaments.

References Cited by the Examiner UNITED STATES PATENTS 1,941,343 12/33 Epp 300-2 2,176,861 10/39 Smith 300-2 2,288,337 6/42 Whittle 300-2 2,303,386 12/42 Peterson 15-182 2,349,643 5/44 Wesemeyer 15-182 2,349,644 5/44 Wesemeyer 300-21 X 2,409,309 10/46 Peterson 15-182 X 2,436,934 3/48 Nielsen et al. 300-21 X 2,626,414 1/53 Nelson et al 15-182 2,756,109 7/56 Nelson et al 300-2 2,932,051 4/60 Mertes 15-182 2,977,622 4/61 Nielsen et al. 15-182 3,038,759 6/ 62 Tilgner 15-182 X 3,042,951 7/62 Tilgner 15-182 FOREIGN PATENTS 269,249 4/27 Great Britain.

CHARLES A. WLLLMUTH, Primary Examiner. 

4. A METHOD OF CONTINUOUSLY FORMING A HELICAL BRUSH MEANS FROM A PREFORMED PREASSEMBLED BRUSH STRIP MEANS INCLUDING A CHANNEL-LIKE BASE MEMBER, A GENERALLY UNIFORM LAYER OF BRISTLES EXTENDING FROM SAID BASE MEMBER, AND A RETAINER ELEMENT FOR SAID BRISTLES WITHIN SAID BASE MEMBER, COMPRISING THE STEPS OF: LONGITUDINALLY MOVING SAID PREASSEMBLED BRUSH STRIP MEANS INTO A CURVED PATH AT A SELECTED CONTINUOUS RATE OF MOVEMENT; FORMING A PLURALITY OF OPPOSED SPACED INDENTATIONS IN SAID BASE MEMBER WHILE SAID BRUSH STRIP MEANS CONTINUES ITS MOVEMENT IN SAID CURVED PATH; AND DIRECTING SAID BRUSH STRIP MEANS ALONG A CONTINUATION OF SAID CURVED PATH TO FORM A HELICAL BRUSH MEANS.
 10. A CONTINUOUS HELICAL BRUSH STRIP MEANS COMPRISING: A CONTINUOUS HELICAL BRUSH STRIP MEMBER HAVING CONTINUOUS SPACED IMPERFORATE SIDE WALLS INCLINED INWARDLY, A CORE MEMBER BETWEEN SAID SIDE WALLS, BRUSH FILAMENTS EXTENDING BETWEEN SAID SIDE WALLS AND BENEATH THE CORE MEMBER, SAID SIDE WALLS HAVING LONGITUDINALLY EXTENDING EDGE MARGINS INITIALLY PRESSED TOWARD EACH OTHER TO PROVIDE A DEFORMED STRESSED ZONE CONTINOUS ALONG AND AT TOP PORTIONS OF THE SIDE WALLS FOR CLAMPING SAID FILAMENTS IN ADDITION TO THE INWARD INCLINATION OF SAID SIDE WALLS, SAID EDGE MARGINS AT SAID ZONE BEING PERIPHERALLY STRETCHED, SAID EDGE MARGINS AT SAID ZONE HAVING A PLURALITY OF SPACED INDENTATIONS THEREIN TO FURTHER STRESS AND DEFORM SAID ZONE, SAID EDGE MARGINS BETWEEN SAID SPACED INDENTATIONS CONVERGING AGAINST SAID FILAMENTS IN OPPOSED PERIPHERAL CURVES, SAID INDENTATIONS TERMINATING WITH INNER ENDS THEREOF SPACED ABOVE SAID CORE MEMBER FOR CLAMPING RETENTION AND GROUPING OF SAID FILAMENTS. 